Extracellular matrix constituting connective tissues, represented by collagen and proteoglycan is metabolized by a group of proteases referred to as matrix metallo-proteinase (hereinafter abbreviated as MMPs in some cases). As MMPs, there are known at present 23 enzymes such as collagenase (referred to also as matrix metallo-proteinase-1 or MMP-1), gelatinase A (referred to also as matrix metallo-proteinase-2 or MMP-2), stromelysin (referred to also as matrix metallo-proteinase-3 or MMP-3), gelatinase B (referred to also as matrix metallo-proteinase-9 or MMP-9), collagenase 3 (referred to also as matrix metallo-proteinase-13 or MMP-13) and membrane-bound matrix metallo-proteinase-1 (e.g. MT1-MMP and MMP-14). The amount of the extracellular matrix in a living body is strictly controlled by endogenous inhibitors of MMPs (e.g. TIMP (tissue inhibitor of matrix metallo-proteinase)). However, when such a balance is disturbed, the enzyme activity of MMP is abnormally enhanced, resulting in various diseases accompanied by the destruction of connective tissues as symptom.
As the diseases, there are exemplified arthrosis deformans (also known as osteoarthritis) and chronic articular rheumatism (also known as rheumatoid arthritis) which are accompanied by the destruction of articular cartilage. As MMPs which participate in arthrosis deformans and chronic articular rheumatism, there are exemplified stromelysin and collagenase 3 etc. (see Annals of the Rheumatic Diseases. 59(6):455-61 (2000) and Journal of Clinical Investigation. 99(7):1534-45 (1997)).
In addition, MMPs are enzymes capable of decomposing basement membrane and participate in the infiltration of cancerous cells into vascular endothelium from peripheral tissues, namely, cancer metastasis. As such MMPs, gelatinases A and B are exemplified (see Pancreas. 24(2):169-78 (2002)).
The therapeutic or preventive effect of MMP inhibitors on the above-exemplified diseases is revealed by J. Exp. Med., 182, 449-457 (1995), Inflamm. Res, 44, S117-S118 (1995), British J. Pharmacol., 121, 540-546 (1997), Inflamm. Res, 49, 144-146 (2000), Am. J. Clin. Oncol., 22, 247-252 (1999), Osteoarthritis and Cartilage, 10, 785-791 (2002), etc. Therefore, MMP inhibitors are considered effective as therapeutic or preventive agents for chondrodegenerative diseases (e.g. arthrosis deformans, chronic articular rheumatism), cancers, etc.
As MMP inhibitors, many compounds are known (see Exp. Opin. Ther. Patents, 8, 259-282 (1998)). There may be exemplified 2-benzylbenzothiazin-3-one compounds (International Publication No. WO00/63197 pamphlet and Japanese Patent Unexamined Publication JP-A-2002-12876).
However, an MMP inhibitor capable of exhibiting a more remarkable effect in a living body is desired even now.
On the other hand, a process for producing a benzothiazin-3-one compound is disclosed in International Publication No. WO00/63197 pamphlet and is thus well known. In addition, there have been reported a process in which an α-bromocarboxylic acid derivative is condensed with a thiophenol derivative in DMF (see Chem. Pharm. Bull., 39, 2888 (1991)) and a process in which the hydroxyl group of an α-hydroxycarboxylic acid is converted to a trifluoromethanesulfonyloxy group in acetonitrile, followed by condensing with a nucleophile in one pot (see Tetrahedron. Asymmetry, 3, 715 (1992)). However, there has been a desire for a process for efficient production of an optically active α-phenylthiocarboxylic acid derivative with little racemization.
As a process for producing an α-hydroxycarboxylic acid as an intermediate for production of the above-mentioned benzothiazin-3-one compound, there are known, for example, the process using baker's yeast disclosed in Japanese Patent Unexamined Publication JP-A-10-84987; the process of carrying out catalytic asymmetric hydrogenation which is disclosed in Japanese Patent Unexamined Publication JP-A-10-120621, with a hydantoin derivative disclosed in Japanese Patent Unexamined Publication JP-A-2000-309575; the process using Grignard reaction of a chiral epoxide compound disclosed in Japanese Patent Unexamined Publication JP-A-2000-37761; and the process using DIP-Cl and disclosed in Tetrahedron Lett., 39, 5501 (1998). However, there has been a desire for a process for producing an α-hydroxycarboxylic acid with a high optical purity in higher yield.